/*
 * [The "BSD license"]
 *  Copyright (c) 2012 Terence Parr
 *  Copyright (c) 2012 Sam Harwell
 *  All rights reserved.
 *
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions
 *  are met:
 *
 *  1. Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *  2. Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *  3. The name of the author may not be used to endorse or promote products
 *     derived from this software without specific prior written permission.
 *
 *  THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 *  IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 *  OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 *  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 *  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 *  NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 *  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 *  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 *  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package org.codefinger.dao.antlr.v4.runtime.misc;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.LinkedHashSet;
import java.util.List;

/**
 * A HashMap that remembers the order that the elements were added. You can
 * alter the ith element with set(i,value) too :) Unique list. I need the
 * replace/set-element-i functionality so I'm subclassing LinkedHashSet.
 */
public class OrderedHashSet<T> extends LinkedHashSet<T> {
	/** Track the elements as they are added to the set */
	protected ArrayList<T>	elements	= new ArrayList<T>();

	public T get(int i) {
		return elements.get(i);
	}

	/**
	 * Replace an existing value with a new value; updates the element list and
	 * the hash table, but not the key as that has not changed.
	 */
	public T set(int i, T value) {
		T oldElement = elements.get(i);
		elements.set(i, value); // update list
		super.remove(oldElement); // now update the set: remove/add
		super.add(value);
		return oldElement;
	}

	public boolean remove(int i) {
		T o = elements.remove(i);
		return super.remove(o);
	}

	/**
	 * Add a value to list; keep in hashtable for consistency also; Key is
	 * object itself. Good for say asking if a certain string is in a list of
	 * strings.
	 */
	@Override
	public boolean add(T value) {
		boolean result = super.add(value);
		if (result) { // only track if new element not in set
			elements.add(value);
		}
		return result;
	}

	@Override
	public boolean remove(Object o) {
		throw new UnsupportedOperationException();
	}

	@Override
	public void clear() {
		elements.clear();
		super.clear();
	}

	@Override
	public int hashCode() {
		return elements.hashCode();
	}

	@Override
	public boolean equals(Object o) {
		if (!(o instanceof OrderedHashSet<?>)) {
			return false;
		}

		// System.out.print("equals " + this + ", " + o+" = ");
		boolean same = elements != null && elements.equals(((OrderedHashSet<?>) o).elements);
		// System.out.println(same);
		return same;
	}

	@Override
	public Iterator<T> iterator() {
		return elements.iterator();
	}

	/**
	 * Return the List holding list of table elements. Note that you are NOT
	 * getting a copy so don't write to the list.
	 */
	public List<T> elements() {
		return elements;
	}

	@Override
	public Object clone() {
		@SuppressWarnings("unchecked")
		// safe (result of clone)
		OrderedHashSet<T> dup = (OrderedHashSet<T>) super.clone();
		dup.elements = new ArrayList<T>(this.elements);
		return dup;
	}

	@Override
	public Object[] toArray() {
		return elements.toArray();
	}

	@Override
	public String toString() {
		return elements.toString();
	}
}
